顺丁橡胶复合材料及其失效机制研究
发布时间：2018-11-28 11:43
【摘要】：橡胶是一种高弹性高分子柔性材料,具有金属材料、无机非金属材料所不具有的性质,在国民生产中有着重要的应用,常用来制造轮胎等动态条件下使用的制品。由于橡胶这种具有熵弹性的高分子链导热性较差,很容易在动态疲劳过程中使橡胶制品产生微小裂纹,致使橡胶制品原有的特性和疲劳寿命大大降低,对于生产生活应用造成不小损失。本文针对橡胶原料中极具耐寒性和抗老化性能优异的顺丁橡胶(BR)作为实验研究的基底材料,通过炭黑、白炭黑的填充以及与天然橡胶共混复合来探究顺丁橡胶的裂纹的产生以及开裂机理;然后从宏观和微观角度相结合去解释裂纹的生长过程,总结出橡胶动态疲劳失效的新理论,对于延长橡胶在动态过程中的使用寿命提出新思路。在论文讨论的第一部分中,通过使用不同粒径的白炭黑填充顺丁橡胶,在橡胶体系中构筑不同的填料网络结构来研究裂纹的生长以及扩展形态,发现并提出粒子形态的规整性对顺丁橡胶性能产生强烈的影响。通过在白炭黑填料中加入硅烷偶联剂(Si69)进行对比试验进一步表明,提升粒子与橡胶基体的相互作用可以有效的降低顺丁橡胶裂纹扩展速度。此外,也表明白炭黑与硅烷偶联剂有效接枝率,即硅烷偶联剂两端分别连接橡胶分子链与纳米粒子,也是调控橡胶裂纹扩展速度的关键。在第二部分中,通过对同一粒径不同份数的炭黑填充顺丁橡胶,将其性能进行横向对比,实验结果表明,炭黑的填充份数与机械性能存在竞争关系。随着炭黑填充份数的增加,其补强的顺丁橡胶复合材料的力学及其他机械性能明显增加;但是炭黑填充份数过多则导致其在橡胶基体内形成聚集体,影响自身性能的发挥。所以,探究合适炭黑填充份数对于降低橡胶裂纹扩展的速率则显得尤为重要。在第三部分中,由于天然橡胶与顺丁橡胶的相容性较好,通过不同比例共混所产生的不同的相态结构探究与橡胶裂纹扩展的关系。实际的测速结果与扫描探针显微镜拍摄的相图结合分析表明,共混体系中相尺寸越小,相界面越模糊,越易降低裂纹生长的速率,我们得出裂纹尖端的应力集中容易在薄弱的相界面进行能量释放,从而破坏顺丁橡胶基体结构而导致橡胶制品疲劳失效。
[Abstract]:Rubber is a kind of high elastic polymer flexible material, which has the properties of metal material and inorganic nonmetallic material. It has important application in national production, and is often used to manufacture products under dynamic conditions such as tire. Because of the poor thermal conductivity of rubber, a polymer chain with entropy elasticity, it is easy to produce tiny cracks in the dynamic fatigue process of rubber products, thus greatly reducing the original characteristics and fatigue life of rubber products. For the production and life of the application caused no small loss. In this paper, cis-butadiene rubber (BR), which has excellent cold-resistance and anti-aging properties in rubber raw materials, was used as the substrate material of experimental study. The crack generation and cracking mechanism of cis-butadiene rubber were investigated by filling with silica and blending with natural rubber. Then the new theory of dynamic fatigue failure of rubber is summarized from the view of macroscopic and microcosmic to explain the growth process of crack, and a new idea for prolonging the service life of rubber in dynamic process is put forward. In the first part of the thesis, the crack growth and propagation morphology were studied by using different particle size silica filled with cis-butadiene rubber and constructing different filler network structure in rubber system. It was found that the regularity of particle morphology had a strong effect on the properties of cis-butadiene rubber. By adding silane coupling agent (Si69) into silica filler, it is further shown that the interaction between the lifting particles and the rubber matrix can effectively reduce the crack growth rate of cis-butadiene rubber. In addition, it is also shown that the effective grafting rate of silica and silane coupling agent, that is to say, the two ends of silane coupling agent are connected with rubber molecular chain and nanoparticles respectively, is also the key to regulate the crack growth rate of rubber. In the second part, the properties of cis-butadiene rubber filled with carbon black with the same particle size and different content were compared horizontally. The experimental results showed that the filling fraction of carbon black had a competitive relationship with the mechanical properties. The mechanical and other mechanical properties of the reinforced cis-butadiene rubber composites increased with the increase of carbon black filling fraction, but too many carbon black fillers resulted in the formation of aggregates in the rubber matrix, which affected the exertion of the properties of the composites. Therefore, it is very important to find out the appropriate fraction of carbon black to reduce the rate of rubber crack growth. In the third part, due to the good compatibility between natural rubber and cis-butadiene rubber, the relationship between the different phase structure and the crack propagation of rubber was investigated by mixing with different proportion. The combination of the actual velocity measurement results and the phase diagram taken by the scanning probe microscope shows that the smaller the phase size is, the more fuzzy the phase interface is and the easier it is to reduce the rate of crack growth. It is concluded that the stress concentration at the crack tip is easy to release energy at the weak phase interface, thus destroying the matrix structure of cis-butadiene rubber and resulting in fatigue failure of rubber products.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ333.2;TB33
本文编号：2362732
[Abstract]:Rubber is a kind of high elastic polymer flexible material, which has the properties of metal material and inorganic nonmetallic material. It has important application in national production, and is often used to manufacture products under dynamic conditions such as tire. Because of the poor thermal conductivity of rubber, a polymer chain with entropy elasticity, it is easy to produce tiny cracks in the dynamic fatigue process of rubber products, thus greatly reducing the original characteristics and fatigue life of rubber products. For the production and life of the application caused no small loss. In this paper, cis-butadiene rubber (BR), which has excellent cold-resistance and anti-aging properties in rubber raw materials, was used as the substrate material of experimental study. The crack generation and cracking mechanism of cis-butadiene rubber were investigated by filling with silica and blending with natural rubber. Then the new theory of dynamic fatigue failure of rubber is summarized from the view of macroscopic and microcosmic to explain the growth process of crack, and a new idea for prolonging the service life of rubber in dynamic process is put forward. In the first part of the thesis, the crack growth and propagation morphology were studied by using different particle size silica filled with cis-butadiene rubber and constructing different filler network structure in rubber system. It was found that the regularity of particle morphology had a strong effect on the properties of cis-butadiene rubber. By adding silane coupling agent (Si69) into silica filler, it is further shown that the interaction between the lifting particles and the rubber matrix can effectively reduce the crack growth rate of cis-butadiene rubber. In addition, it is also shown that the effective grafting rate of silica and silane coupling agent, that is to say, the two ends of silane coupling agent are connected with rubber molecular chain and nanoparticles respectively, is also the key to regulate the crack growth rate of rubber. In the second part, the properties of cis-butadiene rubber filled with carbon black with the same particle size and different content were compared horizontally. The experimental results showed that the filling fraction of carbon black had a competitive relationship with the mechanical properties. The mechanical and other mechanical properties of the reinforced cis-butadiene rubber composites increased with the increase of carbon black filling fraction, but too many carbon black fillers resulted in the formation of aggregates in the rubber matrix, which affected the exertion of the properties of the composites. Therefore, it is very important to find out the appropriate fraction of carbon black to reduce the rate of rubber crack growth. In the third part, due to the good compatibility between natural rubber and cis-butadiene rubber, the relationship between the different phase structure and the crack propagation of rubber was investigated by mixing with different proportion. The combination of the actual velocity measurement results and the phase diagram taken by the scanning probe microscope shows that the smaller the phase size is, the more fuzzy the phase interface is and the easier it is to reduce the rate of crack growth. It is concluded that the stress concentration at the crack tip is easy to release energy at the weak phase interface, thus destroying the matrix structure of cis-butadiene rubber and resulting in fatigue failure of rubber products.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ333.2;TB33
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